Over 15 million family caregivers (CGs) provide more than 85% of long-term care to older adults with Alzheimer?s Disease and Related Dementias (ADRD). CGs typically assume care responsibilities without training or support and may in turn experience multiple health risks including depression. Providing evidence-based CG supportive programs on a wide scale basis is identified by the National Alzheimer?s Plan Act as a national priority. One approach is to augment existing community-based services for older adults with a CG evidence-based program. Adult day service (ADS) is one such growing and critical community-based option for older adults with ADRD but which does not systematically address common CG challenges or burdens using evidence-based programs. Building on other Alzheimer?s informed caregiver interventions including the NIH REACH initiative, we previously developed and evaluated in a small trial, ADS Plus, a program augmenting ADS with systematic support to CGs. We showed that ADS Plus in comparison to usual ADS, reduced CG depression and nursing home placement and enhanced efficacy managing behavioral symptoms over 12 months. ADS Plus consists of 5 key components: care management, referral/linkage, education about dementia, situational counseling/emotional support/stress reduction techniques, and skills to manage behavioral symptoms (e.g., rejection of care, agitation, aggression). Based on care challenges identified by family caregivers, an ?ADS Plus Prescription? is provided, a written document detailing easy-to-use strategies to address specified care challenges and CGs are trained in their use. Our study will employ a practical trial design to assess the effectiveness and uptake of ADS Plus on a large scale. Thirty ADS programs throughout the U.S. varying in location and staffing levels will be involved. A total of 300 diverse CGs (150 in 15 ADS Plus sites; 150 in 15 ADS usual care sites) will be enrolled. We will use cluster and re-randomization techniques, mixed methods, and cost analyses to rigorously evaluate program effectiveness and implementation processes. A Translation Advisory Board composed of key ADS leaders, will provide ongoing advisement concerning integration and uptake of ADS Plus. Our primary specific aims are to: 1) evaluate the effectiveness of ADS Plus to improve CG well-being and reduce depressive symptoms compared to routine ADS use at 6 months; and 2) evaluate long-term maintenance effects of ADS Plus at 12 months on CG well-being and depressive symptoms. Secondary study aims are to: 3) evaluate whether CGs using ADS Plus are more likely to maintain relatives in ADS and less likely to place them in residential settings compared to those in routine ADS over 12 months; 4) estimate ADS Plus costs and assess whether it results in net financial benefits when compared to usual ADS at 6 and 12 months; 5) evaluate the effects of ADS Plus on client dementia-related behaviors and CG efficacy and upset managing symptoms; and 6) evaluate theoretically-derived (RE-AIM, Stress Process Model) mediational pathways of treatment outcomes and staff uptake.